SILRES® BS 38NM is a solvent-based mixture of silane, siloxane and fluoropolymer (< C8). In diluted form, it serves to render inorganic substrates such as mineral construction materials water-repellent and oil-repellent. Unlike conventional impregnating agents, which display only a hydrophobic, i. e. water-repellent, effect, SILRES® BS 38 also exhibits an oleophobic, i. e. oilrepellent, effect. The pores of the substrate remain open, the water vapour diffusion is hardly affected, if at all. Oil, grease and paint, etc. can be more easily removed from surfaces that have been treated with SILRES® BS 38NM.